In 1835, Washington, D.C., was a city in transition: Newly freed African-Americans were coming north and for the first time beginning to outnumber the city's slaves. That demographic shift led to a violent upheaval — all but forgotten today.

Few of the city's buildings from that time remain, but you can still sense what it was like, if you sit in a park by the White House, as NPR's Steve Inskeep did with writer Jefferson Morley.

"The White House was very much as it is today," Morley says. "In the summer of 1835 it was a little shabby because they were constructing a new driveway, and there were workmen's materials all over the place, and people thought that was a little not quite appropriate, but that's the way it was for a year or two."

The look was appropriate, in a way, because American democracy was very much under construction in the 1830s. And Morley brings to light a lost tale of that evolving society in his new book, Snow-Storm in August: Washington City, Francis Scott Key, and the Forgotten Race Riot of 1835 — a tale that begins in that very park by the White House.

"On Aug. 4, 1835, there was a young man loitering here with a friend," Morley says. "He was 19 years old, a black kid, his name was John Arthur Bowen. ... He was the property of a woman named Anna Maria Thornton." Bowen had just come from a meeting of the Talking Society, a group run by a local schoolteacher dedicated to educating slaves and working for their freedom.

It was not the kind of activity that made white people comfortable. A Virginia slave revolt a few years had spurred some Americans to call for slavery's abolition — and also infuriated slave owners. So it was a dangerous environment for a young black man to leave a political meeting, and go out drinking in a park beside the White House.

Morley says Bowen was most likely pretty drunk when he headed back to the Thornton home nearby at 13th and F streets NW. "He picks up an ax, and he goes upstairs ... and on the first floor is where his mother sleeps in the same room with Mrs. Thornton, the woman who owns him. And at about 1 o'clock in the morning, he opens the door to their room and walks in. And his mother and Mrs. Thornton wake up to this sight of this young man standing in the door with an ax in his hand."

Bowen made no move, but Mrs. Thornton screamed, ran to the front door, and began shouting for her neighbors. "And this story starts to spread that Mrs. Thornton has been attacked in her bedroom by a slave with an ax," Morley says. Bowen was arrested for attempted murder after the story reached the ears of local law enforcement.

"A lot of whites thought that [Bowen] attacking his mistress was the beginning of a slave rebellion," Morley continues — which led to a lynch mob gathering at the jail in D.C.'s Judiciary Square, where the young man was being held.

The idea that a black man had possibly attacked a white woman added to the story's power — even though Mrs. Thornton, once she had recovered from her shock, was quick to tell people that Bowen had not meant to hurt her. "And nobody wanted to hear that," Morley says, "least of all, the district attorney, Francis Scott Key."

Yes, the man who wrote "The Star-Spangled Banner" in 1814 was, by 1835, a prominent lawyer. "In a lot of ways, he was really the prototype of the modern Washington lawyer-lobbyist," Morley says. "He had a nice house in Georgetown, he had nice neckties, he had a wine cellar, he had clients who paid big retainers." Morley calls Key a "political operator," who used his fame and his law practice as an entree into politics.

Key's political hero was President Andrew Jackson, who repaid his loyalty with an appointment as D.C.'s top law enforcement official. "So that is how Francis Scott Key came to prosecute Arthur Bowen," Morley says. "When this type of racially charged incident erupted, Key wanted to prove right away that he was in control, and that there was no threat to the slave order in Washington."

But Key couldn't control the fear and resentment of the white mob that had formed in the city. "And the mob just destroyed everything. The black schools, the black churches, the homes of the free blacks," Morley says. "They kind of ran wild, and the law enforcement was just nowhere to be seen. ... This went on for a couple of nights."

Washington hadn't seen that kind of destruction since the British invasion more than 20 years before. "Shock is hardly the word," Morley says. "This wasn't a foreign army that did the damage; this was Americans."

Morley says the riots of 1835 still resonate today — even though few people remember them. "The political debates about free speech, about property rights, about citizenship rights, those are actually still with us. And in fact, this is really when the formative moment of American politics really comes about, and you have this dynamic that we still have with us today: the red and the blue, right? The red states are conservative; the blue states are liberal. A lot was the same."